Abrasive pack with anchor assembly

ABSTRACT

An abrasive pack and anchor assembly for mounting, in plurality, on an axial hub to provide an abrasive drum. The hub is of the type having a substantially cylindrical surface, with substantially longitudinal slots recessed into said surface, each of said slots receiving one of said packs. The abrasive pack of the invention is a laminar assembly of abrasive strips having a length substantially the length of the slotted hub. The base portions of said strips are bonded together by adhesive, and preferably, are compressed to form a relatively solid base structure having a flat planar base surface adapted to seat on the bottom of the slot. The base structure of the pack is transversely pierced at longitudinally spaced intervals by transverse apertures. A reusable anchor member is comprised of a retainer bar seating on one sidewall of said base structure; with short transverse bar members extending laterally of said retainer bar, and integral therewith, at longitudinal spacing corresponding to the spacing of said apertures in the base structure of said pack. When said anchor member is assembled to one of said laminar packs, and drawn longitudinally into one of said hub slots, the abrasive pack assembly is retained in position in said slot.

United States Patent Block July 25, 1972 [54] ABRASIVE PACK WITH ANCHOR ASSEMBLY [72] Inventor: Aleck Block, Los Angeles, Calif.

[73] Assignee: Merit Abrasive Products, Inc., Compton,

Calif.

[22] Filed: Dec. 7, 1970 [21] App]. No.: 95,630

Related [1.8. Application Data [63] Continuation-impart of Ser. No. 643,101, June 2,

1967, Pat. No. 3,548,551.

3,212,219 10/1965 Gillett ..5 H337 Primary Examiner-Donald 0. Kelly Attorney-Hueber & Warrel [57] ABSTRACT An abrasive pack and anchor assembly for mounting, in plurality, on an axial hub to provide an abrasive drum. The hub is of the type having a substantially cylindrical surface, with substantially longitudinal slots recessed into said surface, each of said slots receiving one of said packs. The abrasive pack of the invention is a laminar assembly of abrasive strips having a length substantially the length of the slotted hub. The base portions of said strips are bonded together by adhesive, and preferably, are compressed to form a relatively solid base structure having a flat planar base surface adapted to seat on the bottom of the slot. The base structure of the pack is transversely pierced at longitudinally spaced intervals by transverse apertures. A reusable anchor member is comprised of a retainer bar seating on one sidewall of said base structure; with short transverse bar members extending laterally of said retainer bar, and integral therewith, at longitudinal spacing corresponding to the spacing of said apertures in the base structure of said pack. When said anchor member is assembled to one of said laminar packs, and drawn longitudinally into one of said hub slots, the abrasive pack assembly is retained in position in said slot.

9 Claim 3 Drawing Figures Patented July 25, 1972 JvrEA rae A 1.56/5 3406K,

,QrmRA/Eg ABRASIVE PACK WITH ANCHOR ASSEMBLY This application is a continuation-in-part of US. Pat. application Ser. No. 643,101, of Aleck Block, filed June 2, 1967, for FLAP-TYPE ABRASIVE WHEEL," now Patent No. 3,548,551, granted December 22, 1970.

This invention relates to abrasive drums of the type disclosed, and described in several forms, in the parent application. Such abrasive drums are a recent development differing from the previously known abrasive wheel in that they have relatively great axial length, usually being 6 to 10 feet long, and l to 2 feet in diameter. Such drums have been developed very recently for the continuous polishing of long metal sheets as they emerge from the rolling mill, and for similar uses. Much of the technology found satisfactory with abrasive wheels have proven unsatisfactory for the construction of abrasive drums.

The parent application disclosed a type of an abrasive drum comprised of a large number of abrasive packs mounted on a long hub, in circumferential spacing around the hub, by anchoring the base of each pack in a corresponding slot recessed into the cylindrical surface of the hub. The parent application referred to abrasive drums in which said slots were perfectly straight and parallel to the axis of the hub. However, since the filing of the parent application of this application, abrasive drums using helical slots have been developed by the same inventor and are the subjects of a copending US. Pat. application, Ser. No. 764,243, filed Jan. 27, 1969, by the same inventor, Aleck Block, who is the inventor of this application and of the parent application of this case. It will be appreciated from the following description, that the abrasive pack of the present invention can be adapted to use in the helical slot hub, and the utility of construction of the present invention is not restricted to assembly on hubs having perfectly straight slots. The abrasive pack of the present invention, like most of the species disclosed in the parent application, is comprised of a pack of abrasive strips. The outer edges of said strips open freely from one another, so that the abrasive surface of each strip may separately engage the surface of the workpiece which is being polished or abraded. The radially inner, or base edges of the strips are bonded together into a unitary base structure which is received into one of the slots of the hub, preferably seating on the base of the slot. In the much preferred form of the invention, the base portions of the abrasive strips are bonded with an impregnating resin or plastic material into a unitary solid base structure.

The transverse cross section of the slot is such that the slot opening is restricted, and the radially inner portion of the slot is enlarged. The present invention may be employed with slots of almost any transverse cross section, provided only that there is some longitudinal restriction in the slot, or at its opening, under which an enlargement of the pack base may make engagement for anchoring of the abrasive pack to the hub.

It will be appreciated that abrasive packs wear out after a certain period of use. In the case of most abrasive wheels the entire wheel could be discarded. In the case of abrasive drums, however, it is not economic to discard the massive and expensively constructed hub. Consequently, the abrasive pack and mounting therefor must be of a construction for replacement of abrasive packs at the customer's plant, as well as assembly of said packs on the hub at the time of original manufacture.

The other species of the parent application employed anchoring means which were integrally assembled with the pack of abrasive strips. In the present application, however, the anchor is an entirely separate bar means which is reused with one pack of strips after another, as they are replaced on the hub.

The construction and use of the abrasive pack of the invention will be best understood from the following description of a preferred fonn, which is illustrated in the accompanying drawings, in which:

FIG. 1 is a fragmentary perspective view of one end of an abrasive drum, constructed according to the present invention (with most of the abrasive packs removed for purposes of compact illustration);

FIG. 2 is a fragmentary detail, showing a few slots of the drum of FIG. 1 in transverse cross section, and one abrasive pack and anchor assembly mounted therein; and

FIG. 3 is an exploded perspective view of the pack of abrasive strips and anchor which are assembled to form the abrasive pack of the invention, both pack of strips and anchor being shown in one end fragment portion only, for reasons of compact illustration.

In FIG. 1, the drum of the invention is indicated generally by the numeral 10 and is seen to be comprised of a shaft 11, a hub 12, and a plurality of abrasive packs indicated collectively by the numeral 20, and individually by the numerals 21, 22, 23, 24, etc.

It is seen that hub 12 has a substantially cylindrical surface 30, but that this surface is broken at circumferentially spaced intervals by a large number of slots indicated typically by the slots 31, 32, 33, and 34, which receive the packs 21 to 24.

The slots 31 to 34 are seen to be perfectly straight and parallel with the axis of shaft 11 and hub 12, but it will be appreciated that the invention includes constructions in which slots 31 to 34 depart slightly from the straight line and are disposed along a slightly helical curve.

FIG. 2 is a fragmentary detail of hub 12, showing slots 31, 32, and 33, and abrasive pack 22, at a sectional plane transverse to the axis of hub 12. Abrasive packs 21 and 23 have been eliminated from the fragmentary detail of FIG. 2. FIG. 2 shows, in end view, an anchor or retainer bar 40 which is used to retain abrasive pack 22 in mounting position in slot 32.

The perspective view of FIG. 3 shows: abrasive pack 32 and anchor or retainer bar 40 disassembled from each other. It will be appreciated that both abrasive pack 22 and anchor bar 40 usually have an actual longitudinal dimension 51 ten to forty times as great as the radial dimension 52; however, for purposes of compact illustration, the pack 22 and retainer bar 40 are broken away at line 53, and only the enlarged end portions are illustrated.

It will be seen that anchor or retainer bar 40 is actually comprised of a longitudinal bar 41, which carries a number of Iongitudinally spaced transverse bars or prongs 42.

It will be seen from the enlarged perspective view of FIG. 3, that the pack 22 is actually comprised. of a large number of separate abrasive strips 60, which have their base portion 61 bonded together and compressed into a solid base structure 62. The bonding of base structure 62 may be augmented by staples or stitching 63.

Base structure 62 is transversely pierced by a number of transverse apertures 64, spaced longitudinally of the entire pack 22, at a spacing which mates with the spacing of transverse bars 42 of the retainer 40. The transverse bars 42 should be long enough to extend entirely through the base structure 62, preferably protruding therefrom at their free ends, their length being greater than the transverse dimension of the openings of the slots in the hub.

The preferred embodiment illustrated in FIGS. 1 to 3 is characterized by certain features found in almost all abrasive drums in which the abrasive packs are mounted in slots which receive a base structure 61 of the pack into the slot (as contrasted to abrasive pack mountings in which the base of the abrasive pack seats on the outer cylindrical surface 30, and only an anchor member is received into the mounting slot). Slot 32 has a flat bottom 32a; it has substantially radial sidewalls 32b and 32c, which converge at the slot opening 32d, symmetrically on both sides of the slot, to a pair of op posite slot shoulders 32c and 32f.

It will also be seen that in the preferred specific embodiment, the base structure 61 is so compressed, and molded into a unit with the plastic adhesive material impregnating it, that it is a substantially unitary structure which is closely received in slot opening 32d. It is preferable that the anchor 40 engages both shoulders 32c and 32f for anchoring purposes as may be seen from the fragmentary cross-sectional detail of FIG. 2. The longitudinal bar 41 of the anchor lies adjacent one side of the base structure 62 and contributes a cross sectional enlargement to the base structure.

On the opposite side of base structure 61, the tips of the transverse bars 42 project through the apertures 64 and outwardly of the side 66 of base structure 61 as seen in FIG. 2. These projecting tips make anchoring engagement under slot shoulder 32c.

However, it will be appreciated that the invention may be modified so that it can be used even if slots 31, 32, 33, 34, etc. are not symmetrical; or do not have shoulders on both sides of the slot. Also, any form of overhanging restriction, regardless of the peculiarities of transverse cross section, may be referred to herein generally as a longitudinal shoulder reducing the opening of the slots.

Ordinarily, the anchor 40 would be made of steel, but a tough and resilient plastic material may be used where resilient deforrnability may be required, for example, in the recently developed helical slot hubs.

It will be seen that the anchor member 40 is reusable, and may be transferred from one worn out pack 32, to a new replacement.

It will be seen that the pack 32 may be constructed with a substantially solidified base 61 of a dimension longitudinally of the pack at least equal in depth of the hub slot in which the pack is to be mounted. The base structure 61 is not only solidified but it is compressed so that a relatively narrow slot may accommodate a pack of abrasive strips which is thicker than the width of the slot opening 32d. Usually, the base portion has been so compressed, for example, with an epoxy resin, that it functions as a substantially solid bar, although resiliently deformable to some degree. There is an increase in the local densities of the pack, with consequent interlocking of the leaves of the pack by penetration of abrasive particles of leaves into adjacent sheet material, all cooperating to form a very strong base structure 61. Since anchor member 40 is reusable, it may be made of good quality and strong construction conforming to substantially any slot structure, and it may be constructed to function with anchor engagement on either one or both sides of the slot 32.

lclaim:

1. An abrasive drum comprising in combination: a hub having longitudinal undercut slots circumferentially spaced along its outer surface region, each slot opening to the periphery of the hub and being restricted by at least one longitudinal slot shoulder, a pack of abrasive strips mounted in each of said slots, said strips of each pack having base portions compressed and secured together to form a base structure for said pack, said base structure having a transverse thickness less than the remainder of said pack and extending through said slot opening, said base structure being provided with transverse apertures at longitudinally spaced intervals from one end of said pack to the other, an anchor for each pack comprising a longitudinal bar seating on one side of said base structure, and having a thickness sufficient to make anchoring engagement under a longitudinal shoulder of said slot, and a plurality of relatively short transverse bars, integral with said longitudinal bar, spaced along said longitudinal bar and inserted through said transverse apertures in said base structure.

2. A combination as defined in claim 1 in which the base portions of the strips in each pack are bonded together.

3. A combination as defined in claim 2 in which said transverse bars protrude from the side of said base structure of said pack opposite to that upon which said longitudinal bar is seated a sufficient distance to make anchoring engagement under a longitudinal shoulder of said slot.

4. A combination as defined in claim 2 in which surfaces of said anchor making anchoring engagement with said slot present a transverse cross sectional profile conforming generally to the transverse cross section of the interior of said slot to make snug anchoring engagement with the walls of said slot.

5. A pack of abrasive leaves and retainer therefor adapted for endwise insertion in an undercut slot in a rotary hub the slot having a peripheral opening of restricted transverse magnitude relative to its undercut portion, the pack comprising a plurality of identical flexible sheets coated at least on one side with abrasive material, means securing said sheets together along one edge, forming a base structure, perforations through said base structure, and an anchoring member comprising an elongated bar dimensioned to lie along one side of the base structure, prongs extending transversely from the elongated bar inserted through the apertures, the anchoring member having a transverse magnitude greater than the thickness of the base structure where the edges are secured, the anchoring member being removable from the assembly by withdrawing the prongs from the apertures.

6. A pack of abrasive leaves and retainer therefor as defined in claim 5 in which said elongated bar of said anchoring member possesses sufficient resilient deformability in longitudinal profile, to permit it to be deformed to follow a slot disposed along a helical line.

7. A pack of abrasive leaves and retainer therefor as defined in claim 5 in which the means securing the sheets together forming the base structure is a bonding agent.

8. A pack of abrasive leaves and retainer therefor as defined in claim 5 in which the means securing the sheets together forming the base structure is a series of staples.

9. An abrasive unit comprising a stack of abrasive leaves, means securing the leaves together in the marginal region of one of their corresponding edges forming a pack base structure, longitudinally spaced transverse apertures in said base structure, and an anchor member removably installed on said base structure comprising a longitudinal bar with transverse bars extending therefrom, the longitudinal bar having a length generally corresponding to the length of the base structure and lying against one side of the latter, the transverse bars having a length generally corresponding to at least the thickness of the base structure and disposed in the apertures of the latter, the anchor member providing a transversely extending shoulder on at least one side of the base structure and serving to retain the stack of leaves in fixed relationship with the anchor member.

* at a t 

1. An abrasive drum comprising in combination: a hub having longitudinal undercut slots circumferentially spaced along its outer surface region, each slot opening to the periphery of the hub and being restricted by at least one longitudinal slot shoulder, a pack of abrasive strips mounted in each of said slots, said strips of each pack having base portions compressed and secured together to form a base structure for said pack, said base structure having a transverse thickness less than the remainder of said pack and extending through said slot opening, said base structure being provided with transverse apertures at longitudinally spaced intervals from one end of said pack to the other, an anchor for each pack comprising a longitudinal bar seating on one side of said base structure, and having a thickness sufficient to make anchoring engagement under a longitudinal shoulder of said slot, and a plurality of relatively short transverse bars, integral with said longitudinal bar, spaced along said longitudinal bar and inserted through said transverse apertures in said base structure.
 2. A combination as defined in claim 1 in which the base portions of the strips in each pack are bonded together.
 3. A combination as defined in claim 2 in which said transverse bars protrude from the side of said base structure of said pack opposite to that upon which said longitudinal bar is seated a sufficient distance to make anchoring engagement under a longitudinal shoulder of said slot.
 4. A combination as defined in claim 2 in which surfaces of said anchor making anchoring engagement with said slot present a transverse cross sectional profile conforming generally to the transverse cross section of the interior of said slot to make snug anchoring engagement with the walls of said slot.
 5. A pack of abrasive leaves and retainer therefor adapted for endwise insertion in an undercut slot in a rotary hub the slot having a peripheral opening of restricted transverse magnitude relative to its undercut portion, the pack comprising a plurality of identical flexible sheets coated at least on one side with abrasive material, means securing said sheets together along one edge, forming a base structure, perforations through said base structure, and an anchoring member comprising an elongated bar dimensioned to lie along one side of the base structure, prongs extending transversely from the elongated bar inserted through the apertures, the anchoring member having a transverse magnitude greater than the thickness of the base structure where the edges are secured, the anchoring member being removable from the assembly by withdrawing the prongs from the apertures.
 6. A pack of abrasive leaves and retainer therefor as defined in claim 5 in which said elongated bar of said anchoring member possesses sufficient resilient deformability in longitudinal profile, to permit it to be deformed to follow a slot disposed along a helical line.
 7. A pack of abrasive leaves and retainer therefor as defined in claim 5 in which the means securing the sheets together forming the base structure is a bonding agent.
 8. A pack of abrasive leaves and retainer therefor as defined in claim 5 in which the means securing the sheets together forming the base structure is a series of staples.
 9. An abrasive unit comprising a stack of abrasive leaves, means securing the leaves together in the marginal region of one of their corresponding edges forming a pack base structure, longitudinally spaced transverse apertures in said base structure, And an anchor member removably installed on said base structure comprising a longitudinal bar with transverse bars extending therefrom, the longitudinal bar having a length generally corresponding to the length of the base structure and lying against one side of the latter, the transverse bars having a length generally corresponding to at least the thickness of the base structure and disposed in the apertures of the latter, the anchor member providing a transversely extending shoulder on at least one side of the base structure and serving to retain the stack of leaves in fixed relationship with the anchor member. 